Factory PCM and Opti limits?
Thread Starter
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Factory PCM and Opti limits?
I've read that the factory PCM can't handle higher rpms and that the OPTISPARK is a grenade at 6000rpm.
I don't buy it..check this out 6972 on my daily driven 355 with an OEM opti from a EBAY supplier...and I'm getting ready for a tune up...plugs have about 10K on them (autolight 104s) and probably 30K on the unmolested opti.....
I don't buy it..check this out 6972 on my daily driven 355 with an OEM opti from a EBAY supplier...and I'm getting ready for a tune up...plugs have about 10K on them (autolight 104s) and probably 30K on the unmolested opti.....
Safety Car
Joined: Aug 2008
Posts: 4,344
Likes: 48
From: San Marcos CA
I do not know what the upper limit is on the opti-system, but it has to be the same as an old HEI or any of the single coil GM systems preceding it. The biggest issue is that it is a single coil and the amount of time it has to reach saturation is a lot less than if you had 4 or 8 coils like on the newest cars. Then there are the cap and rotor losses, the longer plug wire lengths and so on.
You can certainly go higher than 6k rpm, but it gets challenging if you are forced induction or real high cylinder pressure- MSD boxes do tend to boost coil output though.
The other issue, which might be opti-specific is that the optical sensor may get false signals if there are any reflective surfaces in the unit or if the device itself has an signal timing limitation. The old aftermarket Mallory smallblock chevy distributors used optical triggers and if you didn't take steel wool to the inside of the cap or just plain ran it to too high of a load at 6500 rpm plus, it started missing big time.
You can certainly go higher than 6k rpm, but it gets challenging if you are forced induction or real high cylinder pressure- MSD boxes do tend to boost coil output though.
The other issue, which might be opti-specific is that the optical sensor may get false signals if there are any reflective surfaces in the unit or if the device itself has an signal timing limitation. The old aftermarket Mallory smallblock chevy distributors used optical triggers and if you didn't take steel wool to the inside of the cap or just plain ran it to too high of a load at 6500 rpm plus, it started missing big time.
Last edited by mike100; Dec 19, 2009 at 11:08 AM.
Thread Starter
Race Director
Joined: Jan 2005
Posts: 10,641
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From: Slidell Louisiana
Race Director
Joined: Aug 2006
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From: D / FW
Yep designed for 7700 max RPM 's but 7400 would be reasonable .
An engine that lives at those RPM's is likely full race and would be going Mag at that point !
Mines built for 7,000 plus but I limit it to 6200 ! I'm running a stock OPTI even though I have an LSX timing cover with crank trigger !
I haven't found it necessary to put on coil paks yet !
An engine that lives at those RPM's is likely full race and would be going Mag at that point !
Mines built for 7,000 plus but I limit it to 6200 ! I'm running a stock OPTI even though I have an LSX timing cover with crank trigger !
I haven't found it necessary to put on coil paks yet !
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